钢丝损伤对悬索桥吊索承载力影响分析

发布时间：2018-10-16 14:08

【摘要】：悬索桥具有跨度大、轻柔性、用料省等特点,其能充分利用材料的特性而受到桥梁界的青睐。由于在车辆荷载作用下并加上自然界的腐蚀双重作用,使得悬索桥钢丝吊索的安全使用受到了严重的威胁。基于此结合大跨度悬索桥实际工程,研究钢丝吊索损伤情况下对悬索桥吊索结构承载力特性影响分析。运用有限元结构分析软件Midas/Civil对悬索桥进行实体模型的建立,对悬索桥处于不同车辆荷载工况下悬索桥吊索结构的内力变化；其次对工程吊索钢丝材料进行力学拉伸试验,试验分为损伤试验和无损试验,其中损伤试验是对钢丝进行表面刻槽及电化学腐蚀,电化学腐蚀采用外加直流电源的形式进行,腐蚀的程度是以时间和通电电流大小为参数进行试验研究,吊索刻痕深度控制以精度为0.02mm的游标卡尺进行有效控制。研究结果表明：刻痕深度的变化对钢丝的受力位移曲线影响主要表现在曲线的弹塑性阶段和颈缩破坏阶段,而对材料的弹性阶段影响较小。荷载作用下刻痕损伤的吊索钢丝塑性变形随着刻痕深度的增加逐渐的降低,而与刻痕的位置没有关系,随着刻痕深度的增加钢丝吊索的承载力有一定程度的下降,但对整个吊索结构的影响相对较小；而腐蚀的钢丝对吊索结构影响较大,腐蚀改变了材料的力学特性,经过腐蚀的材料,其塑性变形在一开始受力的时候位移就发生较大的变化,这种变化往往是不可逆的,而在弹塑性阶段和颈缩破坏阶段都发生的很快,即达到一定的荷载就发生断裂破坏,这对于受较大冲击力并需要一定伸长变化的吊索而言显然腐蚀材料是不能满足构件的需要,特别是腐蚀特别严重的构件,承载力降低达45%,对构件的安全使用构成了严重的威胁,因此在日常的维修与加固过程中应该重点监测吊索钢丝材料的腐蚀,对腐蚀的材料及早的采取保护或者更换。
[Abstract]:Suspension bridge has the characteristics of large span, soft, and saving materials, and it can make full use of the characteristics of materials, so it is favored by the bridge boundary. Due to the dual action of vehicle load and natural corrosion, the safety of steel wire sling of suspension bridge is seriously threatened. Based on the practical engineering of long-span suspension bridge, the influence of steel wire sling damage on the bearing capacity of suspension bridge structure is studied. The finite element structure analysis software Midas/Civil is used to establish the solid model of suspension bridge, and the internal force of suspension bridge under different vehicle load conditions is changed. Secondly, the mechanical tensile test of steel wire material for engineering sling is carried out. The test is divided into damage test and nondestructive test, in which the damage test is the surface grooving and electrochemical corrosion of the steel wire, and the electrochemical corrosion is carried out in the form of an additional DC power supply. The degree of corrosion is studied with time and current as parameters, and the depth of slings is controlled by Vernier calipers with precision of 0.02mm. The results show that the stress displacement curve of steel wire is mainly affected by the change of indentation depth in the elastic-plastic stage and necking failure stage, but it has little effect on the elastic stage of the material. The plastic deformation of sling steel wire with notch damage under load decreases gradually with the increase of indentation depth, but it has no relation with the location of indentation, and the bearing capacity of sling cable decreases to a certain extent with the increase of indentation depth. However, the influence on the whole sling structure is relatively small, while the corroded steel wire has a great influence on the sling structure, and corrosion changes the mechanical properties of the material, and the corroded material, The plastic deformation changes greatly at the beginning of loading, and this change is often irreversible. However, in the elastic-plastic stage and necking failure stage, the fracture occurs quickly, that is, when a certain load is reached, the fracture failure occurs. It is obvious that the corroded material cannot meet the needs of the members for the slings that are subjected to a large impact force and require certain elongation changes, especially for the particularly serious corroded members, the bearing capacity of which is reduced to 45.5 percent, which poses a serious threat to the safe use of the components. Therefore, in the course of daily maintenance and reinforcement, the corrosion of sling wire material should be monitored, and the corroded material should be protected or replaced as early as possible.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.25

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